Is there a shortcut to open the 3D view?
Shift + F1 - F12 keys 

F5 for 3D view.



F3 = Node Editor

F4 = Console

F5 = 3D View

F6 = Curve editor

F7 = Properties

F8 = VSE

F9 = Outliner

F10 = Image/Uv editor

F11 = Text Editor

F12 = Dopesheet editor

Don't know where timeline went.